zehnpaard https://blog.hatena.ne.jp/zehnpaard/ Arantium Maestum https://zehnpaard.hatenablog.com/ Haskell Thinking Functionally with Haskell Exercise F 第一部 任意の有限リストxsについて、以下の等式が成り立つことを証明せよ： foldl f e xs = foldr (flip f) e (reverse xs) 帰納法で解く。 Case [] 左辺 foldl f e [] = {foldlの定義} e Case [] 右辺 foldr (flip f) e (reverse []) = {reverse [] = []} foldr (flip f) e [] = {foldrの定義} e Case []は証明できた。 Case x:xs 左辺 foldl f e (x:xs) = {foldlの定義} foldl… 190 <iframe src="https://hatenablog-parts.com/embed?url=https%3A%2F%2Fzehnpaard.hatenablog.com%2Fentry%2F2018%2F03%2F28%2F210425" title="Thinking Functionally with Haskell勉強メモ: 第６章問題２ - Arantium Maestum" class="embed-card embed-blogcard" scrolling="no" frameborder="0" style="display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;"></iframe> https://chart.apis.google.com/chart?cht=tx&chl=%7B%5Csum_%7Bn%3D0%7D%5E%7B%5Cinfty%7D%20%5Cfrac%7B1%7D%7Bn%21%7D%20%3D%20e%7D Hatena Blog https://hatena.blog 2018-03-28 21:04:25 rich https://zehnpaard.hatenablog.com/entry/2018/03/28/210425 1.0 100%